Olivopontocerebellar atrophy in a large Iakut kinship in eastern Siberia.

One-hundred cases of olivopontocerebellar atrophy, type 1, were found and studied in the Iakut population of Eastern Siberia. The disease followed a slowly progressive course of cerebellar insufficiency caused by degeneration in the cerebellar cortex, nuclei pontis, and inferior oliva. The disorder shows an autosomal dominant pattern of inheritance with a lower penetrance in females. The disease spread from a small region in the Aldan valley 200 to 300 years ago.